/* istanbul ignore next */
export const hasClass = function (el, cls) {
  if (!el || !cls) return false
  if (cls.indexOf(' ') !== -1) throw new Error('className should not contain space.')
  if (el.classList) return el.classList.contains(cls)
  else return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1
}

/* istanbul ignore next */
export const addClass = function(el, cls) {
  if (!el) return
  var curClass = el.className
  var classes = (cls || '').split(' ')
  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue
    if (el.classList) el.classList.add(clsName)
    else if (!hasClass(el, clsName)) curClass += ' ' + clsName
  }
  if (!el.classList) el.className = curClass
}
/* istanbul ignore next */
const trim = function(string) {
  return (string || '').replace(/^[\s\uFEFF]+|[\s\uFEFF]+$/g, '')
}
/* istanbul ignore next */
export const removeClass = function(el, cls) {
  if (!el || !cls) return
  var classes = cls.split(' ')
  var curClass = ' ' + el.className + ' '
  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue
    if (el.classList) el.classList.remove(clsName)
    else if (hasClass(el, clsName)) curClass = curClass.replace(' ' + clsName + ' ', ' ')
  }
  if (!el.classList) el.className = trim(curClass)
}
